1. Field of the Invention
The present invention relates generally to equipment used in photolithography systems. More particularly, the present invention relates to a system which detects acceleration of a lens system and compensates for vibrations in the lens system substantially without utilizing an accelerometer.
2. Description of the Related Art
In many photolithography systems, vibrations have an adverse effect. For example, if vibrations of a lens barrel of a projection lens arrangement of a photolithography system cause a projection lens to vibrate, images projected by the projection lens arrangement may be distorted. Distortion in projected images may have an adverse impact on the semiconductor wafers formed using the photolithography system. As a result, many photolithography systems detect vibrations, and provide compensation for the vibrations.
Typically, in order to detect vibrations, accelerometers are provided. By way of example, when a projection lens arrangement is subject to vibrations, an accelerometer or similar sensor may generally be placed on an active lens mount of the projection lens arrangement. While the accelerometer may accurately detect vibrations, locating the accelerometer on the active lens mount may be problematic. Adding additional hardware, i.e., a sensor such as an accelerometer, to a projection lens arrangement may be inconvenient and/or uneconomical. In addition, sensors such as accelerometers have a time-delayed response and, further often have noise issues.